x Johanna G. Hodges
gender-based cassava farmers’ climate change awareness and adaptation in the
Niger Delta region of Nigeria. A multistage sampling technique was used to
select 360 cassava farmers (180 male and 180 female) across three (3) States
of Akwa Ibom, Cross Rivers and Ondo out of the nine (9) states that make up
the Niger Delta region. The study employed descriptive statistics and
Multinomial logit regression model for data analysis. Specifically, the study
examined gender-based socio-economic characteristics of cassava farmers;
gender-based climate change awareness of cassava farmers; gender-based
cassava farmers’ constraints to climate change adaptation and examined the
factors influencing gender-based cassava farmers’ choice of adaptation
strategies in the study area.
Chapter 5 – Rice-oilseed rape rotation is one of the long-established major
cropping systems in China. Here, the authors (1) determined the soil fertility
change in a long-term rice-oilseed rape cropping paddy field at the research
farm of Hunan Agricultural University, China from 2004 to 2015, and (2)
conducted a field and a^15 N micro-plot experiment to compare yield attributes,
N uptake and fertilizer-N fate among three N rates, i.e. 150 kg ha–^1
(recommend N rate), 120 kg ha–^1 (80% of the recommend N rate) and 90 kg
ha–^1 (60% of the recommend N rate), on the long-term rice-oilseed rape
cropping paddy field in 2015. Their results showed that soil organic matter,
total N and available N contents in the upper 20 cm layer increased from 15.
g kg–^1 , 1.40 g kg–^1 and 0. 14 g kg–^1 in 2004 to 34.4 g kg–^1 , 1.49 g kg–^1 and 0. 18
g kg–^1 in 2015, respectively. Ratio of available N to total N increased 25%
from 2004 to 2015. In the field experiment, there were no significant
differences in grain yield (11.2–11.6 t ha–^1 ) and total N uptake (196–209 kg
ha–^1 ) among the three N rates. In the^15 N micro-plot experiment, the
differences in total N uptake, N uptake from soil and N uptake from fertilizer
were insignificant among the three N rates. The N uptake form soil and
fertilizer occupied 81–83% and 17–19% of the total N uptake, respectively.
Retention of fertilizer-N in soil did not significantly affected by N rate,
whereas fertilizer-N loss significantly decreased with decreasing N rate. These
results suggest that long-term rice-oilseed rape rotation can increase soil
fertility and consequently reduce the dependence on external N inputs and the
impact on environments in rice production.